D-myo-inositol 1,4,5-trisphosphate [Ins(1,4,5)P.sub.3 ] is generated from the phospholipase C-mediated breakdown of membrane phosphatidylinositol 4,5 bisphosphate [PtdIns(4,5)P.sub.2 ] in response to stimulation by hormones, neurotransmitters, and growth factors, Berridge, M. J., Nature, 1993, 361, 315, and references cited therein. Ins(1,4,5)P.sub.3, in turn, elicits Ca.sup.2+ mobilization and, subsequently, an array of intracellular events by interacting with specific receptors on intracellular organelles, Meldolesi, J.; Villa, A.; Volpe, P.; Pozzan, T., Advanced in Second Messanger and Phosphoproein Research; Putney, J. W., Jr., Ed.; Raven Press: New York, 1992; Vol. 26, pp 187-208. While many researchers assert that the biologically relevant receptors for Ins(1,4,5)P.sub.3 distribute mainly on the membrane of the endoplasmic reticulum or nucleus, others suggest the locality on a more specialized endomembrane fraction, i.e., calciosomes, Volpe, P.; Kraus, K. H.; Sadamitsu, H.; Zorzato, F.; Pozzan, T.; Meldolesi, J.; Low, P. B., Proc. Natl. Acad. Sci, USA, 1988, 85, 1091. In the second phase of the signaling process, i.e., Ca.sup.2+ entry from the extracellular medium, Ins(1,4,5)P.sub.3 has also been implicated. The capacitative entry theory suggests that depletion of the intracellular Ca.sup.2+ store by Ins(1,4,5)P3 generates a secondary signal of unknown nature that activates Ca.sup.2+ entry, Putney, J. W., Jr., Cell Calcium, 1986, 7, 1; Takemura, H.,; Putney, J. W., Jr., Biochem. J., 1989, 258, 409; Putney, J. W., Jr., Advances in Second Messanger and Phosphoprotein Research; Putney, J. W., Jr., Ed.; Raven Press: New York, 1992; Vol. 26, pp 143-160. Thus, the mechanism of interaction between the Ins(1,4,5)P.sub.3 -sensitive Ca.sup.2+ pool and the Ca.sup.2+ channel on plasma membrane (Ins(1,4,5)P.sub.3 -mediated Ca.sup.2+ homeostasis) has not yet been satisfactorily resolved.
The present invention embodies novel Ins(1,4,5)P.sub.3 analogues and the syntheses for such analogues. Although a number of Ins(1,4,5)P.sub.3 analogues have been reported, the reactive appendages of these derivatives were attached to the parent molecule through a C-1 phosphodiester linkage, Prestwich, G. D.; Marecek, J. F.; Mourey, R. J.; Theibert, A. B.; Ferris, C. D.; Danoff, S. K.; Snyder, S. H., J. Am. Chem. Soc.. 1991, 113, 1822; Tegge, W.; Ballou, C. E., Carbohydr. Res., 1992, 230, 63. The present invention, in a preferred embodiment, is directed to the synthesis of two novel Ins(1,4,5)P.sub.3 analogues, 1 and 2, with modification at the C-6 position.
The derivatized Ins(1,4,5)P.sub.3 contains an amine or aldehyde function for further elaborations which allows the preparation of Ins(1,4,5)P.sub.3 -based analogues for antibody induction, affinity purification, and histochemical probing.